Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1056597 | Journal of Environmental Management | 2013 | 7 Pages |
Different activated carbons modified with iron hydro(oxide) nanoparticles were tested for their ability to adsorb arsenic from water. Adsorption isotherms were determined at As (V) concentrations < 1 ppm, with varying pH (6, 7, 8) and temperature (25 and 35 °C). Also, competition effect of anions on the As (V) adsorption capacity was evaluated using groundwater. The surface areas of the modified activated carbons ranged from 632 m2 g−1 to 1101 m2 g−1, and their maximum arsenic adsorption capacity varied from 370 μg g−1 to 1250 μg g−1. Temperature had no significant effect on arsenic adsorption; however, arsenic adsorption decreased 32% when the solution pH increased from 6 to 8. In addition, when groundwater was used in the experiments, the arsenic adsorption considerably decreased due to the presence of competing anions (mainly SO42−, Cl− and F−) for active sites. The data from kinetic studies fitted well to the pseudo-second-order model (r2 = 0.98–0.99). The results indicated that sample CAZ-M had faster kinetics than the other two materials in the first 10 min. However, sample F400-M was only 5.5% slower than CAZ-M. The results of this study show that iron modified activated carbons are efficient adsorbents for arsenic at concentrations lower than 300 μg L−1.
► Surface area, iron content and pH of the adsorbent influence the As (V) uptake. ► As (V) adsorption capacity decreases 32% when the solution pH increases from 6 to 8. ► Temperature does not significantly affect As (V) adsorption capacity. ► SO42−, Cl− and F− compete with As (V) for active sites. ► 30–36% of As (V) is removed by modified carbon materials in the first 10 min.